Phytohormonal regulation of gases exchange in Beta vulgaris L. during water stress
2010
Hejnak, V.,Ceska Zemedelska Univ., Prague (Czech Republic). Katedra Botaniky a Fyziologie Rostlin
The paper assesses the impact of abscisic acid (ABA) and cytokinin benzylaminopurine (BAP) on the control of exchange of gases in the leaves of sugar beet during water stress. Pot experiments with young plants of the Takt variety were carried out under controlled conditions in a greenhouse. ABA in the concentration of 100 microM and BAP in the concentration of 1 microM and 10 microM were applied to the leaves 3 days after the plants had been divided into variants and after irrigation had been interrupted. The relative water content (RWC) in leaves, the photosynthetic rate (PN), the transpiration rate (E) and the water use efficiency (WUE) were measured just before the application of the growth regulators and then 2 hours and 1, 3, 5, 7 and 9 days after the application of the growth regulators. Throughout this period, the plants retained high RWC but there was a significant decrease of PN and E and also an improvement of WUE in comparison with the non-stressed plants. The application of ABA first decreased PN and E in the stressed plants, whereas deterioration of WUE occurred at 2 and 24 hours after the application. At later dates, the levels of PN and E obtained were, conversely, higher, and WUE was approximately the same in comparison with the plants that were stressed but not treated with ABA. The application of BAP on plants stressed by drought resulted in significantly higher levels of PN and E in comparison with the plants not treated by BAP. In the case of joint application of both substances, the identified levels of PN and E were significantly higher than when ABA was applied alone; these levels were almost the same as the levels measured after the application of BAP alone.
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